The disclosure relates to a laser amplifier, a laser apparatus, and an extreme ultraviolet (EUV) light generating system configured to generate EUV light based on pulsed laser light outputted from the laser apparatus.
In recent years, miniaturization of a transcription pattern of an optical lithography in a semiconductor process is drastically progressing with the development in fining of the semiconductor process. In the next generation, microfabrication on the order of 70 nm to 45 nm, and further microfabrication on the order of 32 nm or less are bound to be required. To meet such requirement for the microfabrication on the order of, for example, 32 nm or less, development is anticipated of an exposure apparatus that includes a combination of a reduced projection reflective optics and an extreme ultraviolet light generating apparatus that generates extreme ultraviolet (EUV) light with a wavelength of about 13 nm.
Three types of apparatuses have been proposed for the extreme ultraviolet light generating apparatus, which are a laser produced plasma (LPP) apparatus that uses plasma generated by application of laser light to a target substance, a discharge produced plasma (DPP) apparatus that uses plasma generated by electric discharge, and a synchrotron radiation (SR) apparatus that uses orbital radiation light. For example, reference is made Japanese Unexamined Patent Application Publication No. 2010-103104, Japanese Patent No. 5086677, and U.S. Patent Application Publication No. 2010/0327192.